The invention relates to an optoelectronic detection device comprising at least one transmitter unit for the transmission of electromagnetic radiation, preferably pulsed electromagnetic radiation, at least one receiver unit associated with the transmitter unit and at least one radiation deflection device with which radiation transmitted by the transmitter unit can be guided into a monitored zone and radiation reflected from the monitored zone can be guided onto the receiver unit.
Such detection devices are generally known and are attached to vehicles, for example, to detect the environment of the vehicle during the journey.
It is an object of the invention to provide an optoelectronic detection device of the kind first named which allows a reliable detection of the monitored zone and is designed as simply as possible and which, in particular, has as few moving components as possible.
This object is satisfied in that the front of the radiation propagating in the direction of the deflection device is of elongated shape and the deflection device is made and is movable relative to the elongated radiation front such that the radiation front reflected into the monitored zone adopts different orientations in space in dependence on the position of the moved deflection device.
In accordance with the invention, the scanning of the monitored zone not only takes place with the aid of punctiform radiation transmitted into the monitored zone, but the detection device is able to transmit an elongated radiation front into the monitored zone. The radiation deflection device serves this purpose and deflects the elongated radiation front subsequent to its generation such that the radiation front is transmitted into the monitored zone in an orientation dependent on the position of the deflection device. The scanning of the monitored zone therefore takes place by means of a two-dimensional radiation front whichxe2x80x94together with the movement of the deflection devicexe2x80x94results in a three-dimensional or quasi three-dimensional scanning of the monitored zone. When a correspondingly designed receiver unit is used, individual sections of the reflected elongated radiation front can be evaluated separately; i.e. a section of the respectively scanned object can be recorded for every direction in which the light line or streak is transmitted. Furthermore, different orientations of the radiation front transmitted into the monitored zone can be realized by means of the movable deflection device, whereby the optoelectronic detection device in accordance with the invention can be directly adapted to the respective application.
It is of special advantage for the invention that the deflection device is the only component which has to be moved in order to scan the monitored zone by means of the radiation front. The transmitter unit and the receiver unit, as well as the supply and connection devices associated therewith, do not have to be moved. The design of the detection device in accordance with the invention is hereby substantially simplified. Since the deflection device is moved relative to the propagating radiation front, the orientation of the radiation front does not change with respect to the alignment of the receiver unit; i.e. the orientation of the radiation front is the same before its deflection into the monitored zone, on the one hand, and after reflection in the monitored zone and a repeated deflection back in the direction of the receiver unit, on the other hand. For this reason, it is not necessary to take the different orientations of the radiation front in the monitored zone into account in the design of the receiver unit, which keeps the design of the receiver unit simple.
It is furthermore of advantage in accordance with the invention that no optical components are required for the production of the elongated radiation front which have to move together with the deflection device. The design of the detection device in accordance with the invention is hereby further simplified. In accordance with the invention, an especially low construction height, and thus an advantageous compact design overall, can be realized in particular, since no components which have to be moved together with the deflection device are required between the transmitter unit and/or the receiver unit, on the one hand, and the deflection device, on the other hand, to generate the radiation front.
The transmitter unit is preferably formed to transmit the elongated radiation front. Here, it is the transmitter unit itself which generates the elongated radiation front so that no optical components are needed between the transmitter unit and the radiation deflection device.
In a particularly preferred embodiment of the invention, the radiation front is a continuous radiation line. Consequently, a light line or streak is transmitted into the monitored zone with which objects located in the monitored zone are scanned not line by line, but areally so that a three-dimensional scanning takes place overall.
Alternatively, the elongated radiation front can also be formed by discrete radiation spots or beads arranged along a line in that, for example, a plurality of xe2x80x9clight fingersxe2x80x9d or individual rays are simultaneously directed onto the deflection device, for example by a correspondingly designed transmitter unit. A three-dimensional detection of the monitored zone is also possible in this way.
It is further preferred for the radiation to propagate in an expanding manner in the direction of the deflection device. The origin of the expansion is preferably not moved relative to the transmitter unit and the receiver unit during operation. The origin of the expansion is in particular formed by the transmitter unit.
The radiation propagating from the transmitter unit to the deflection device is preferably uninfluenced by optical components serving for the radiation refraction or diffraction of the radiation. A particularly advantageous compact design of the detection device can hereby be realized.
This compact design, resulting in particular through reduction of the construction height, is a substantial step in the direction of a miniaturization of optoelectronic detection devices, which is in particular of importance for the use on or in vehicles, where there is as a rule little room available for such detection devices. The wind resistance is moreover hereby minimized.
In a particularly preferred practical embodiment of the invention, the deflection device is rotatable and in particular adapted to carry out a continuous rotational movement at a constant speed. A scanning or scanner function is hereby realized with which it is possible to realize scanning over an angular range of up to 360xc2x0 and thus a monitoring of the total environment of the detection device.
The radiation deflection device preferably has at least one planar reflection surface for radiation transmitted by the transmitter unit and reflected from the monitored zone. This reflection surface is preferably a planar mirror. The deflection device is in particular made as a mirror device and/or as a prism device.
It is further proposed that a reflection surface of the deflection device extends in an inclined manner with respect to a transmission plane and/or a reception plane and the deflection device is rotatable about an axis extending approximately perpendicular to the transmission plane and/or the reception plane.
In this way a situation is achieved in which, in a rotated position of the deflection device, the radiation front reflected by the reflection surface into the monitored zone is perpendicular with respect to the transmission plane and/or the reception plane; i.e. a light line is transmitted more or less upright. By further rotation of the deflection device by 90xc2x0, the radiation front transmitted into the monitored zone lies in a plane extending parallel to the transmission plane and/or the reception plane; i.e. the operation is carried out with a more or less horizontally lying light line. In intermediate rotational positions of the deflection device, the radiation front then extends in a more or less inclined manner to the transmission plane and/or the reception plane. With a rotating deflection device, work is consequently carried out with a rotating image or with a rotating light line or streak.
In accordance with a further preferred embodiment of the invention, provision is made for the transmitter unit to include at least one laser diode as a radiation source which is made for the transmission of a linear or streak-shaped radiation front.
Provision is furthermore preferably made for an optical transmission system to be installed in front of a radiation source of the transmitter unit. The radiation source, in particular a laser diode, and the optical transmission system can be combined to form a compact unit. In this way, additional optical components are not required between the transmitter unit and the deflection device for the generation of the elongated radiation front, whereby an advantageous compact construction of the detection device in accordance with the invention is achieved overall.
It is furthermore proposed in accordance with the invention for the receiver unit to have at least one areal radiation receiver. The radiation receiver is preferably matched to the elongated shape of the radiation front and in particular has an approximately strip-like basic shape.
The receiver unit, in particular an areal radiation receiver of the receiver unit, preferably includes a plurality of photodiodes which are in particular arranged in a single-line or multi-line manner.
Provision is preferably further made for the transmitter unit and the receiver unit to form an at least approximately common transmission/reception plane. This transmission/reception plane is in particular formed by an optical transmission system disposed in front of the radiation source as well as by an optical reception system of the receiver unit disposed in front of an areal radiation receiver.
The invention moreover relates to the use of at least one optoelectronic detection device such as was described above in connection with a vehicle. In this connection, the optoelectronic device is in particular used for object recognition and tracking.
In this connection, an optoelectronic detection device is preferably used which is made and is attached to or in the vehicle such that, in normal driving operation, the radiation front comprising an elongated shape extends at least substantially in the vertical direction on propagation toward the front in the direction of travel.
This use has the advantage that height information, for example on vehicles traveling in front of the vehicle equipped with the detection device, can be obtained from the region disposed in front of the vehicle in the direction of travel.
Further preferred embodiments of the invention relating both to the optoelectronic detection device itself and to the use in accordance with the invention are also set forth in the description and the drawing.
The invention will be described in the following by way of example with reference to the drawing.